Back in December of 2011, Consumer Watchdog called on the EPA to investigate Hyundai over its fuel economy claims. According to Consumer Watchdog, Hyundai claimed that its Elantra was good for 29 mpg in the city and 40 mpg on highway. The problem the organization had with the claims is that it received a higher than usual number of complaints that real-world mileage was in the mid-20 mpg range.

The EPA did investigate Hyundai for misleading mileage claims as well as Kia, and changes in fuel economy estimates are coming as a result of the investigation. Both Kia and Hyundai will be lowering the fuel economy estimates on the majority of their 2012 to 2013 models after EPA testing discovered discrepancies between its data and the company's data.

Hyundai and Kia admitted to overstating the estimated fuel economy on window stickers of about 900,000 vehicles sold since late 2010. The two automakers will reportedly spend millions of dollars to compensate owners for faulty claims of economy.

Hyundai will also have to retract its widely used claim that it leads the industry with four vehicle models able to get 40 mpg on the highway. That statement will be retracted because estimated highway economy on the 2013 Accent, Veloster, and Elantra are being reduced to below 40 mpg.

Some of the biggest losers include the Hyundai Accent and the all-new, redesigned 2013 Hyundai Santa Fe. The Accent saw its 30/40/33 (city/highway/combined) rating drop to 28/37/31. The Santa Fe Sport (2WD) saw a huge drop in its highway rating, going from 21/31/25 (city/highway/combined) to 20/27/23.

Many of the mileage adjustments take Hyundai models from being class leaders to either middle-of-the-pack or lower.

On the Kia side of things, the Soul took the biggest hit as it saw its highway numbers drop by 6 mpg (35 mpg highway to 29 mpg highway).

Overstating fuel efficiency is a significant blunder by the two car companies because gas prices are up, and many people are shopping based on fuel economy claims by the manufacturer. The EPA notes that window sticker values have previously been reduced on only two vehicles sense 2000, so that makes Hyundai’s folly even more egregious.

"Given the importance of fuel efficiency to all of us, we're extremely sorry about these errors," said Hyundai Motor America President and CEO John Krafcik. "We're going to make this right."

Krafcik blamed the inaccurate fuel efficiency claims on "procedural errors" in the fuel-economy testing methodology the company used. Hyundai-Kia's combined fleetwide fuel economy average declined from 27 MPG to 26 mpg for the 2012 model year working out to about a 3% reduction.

Krafcik added, "We've identified the source of the discrepancies between our prior testing method and the EPA's recommended approach."

quote: but it is an issue that the EPA testing does not properly test for real world use.

Once again, the EPA mileage estimates are not predictions of the real world fuel mileage that you will get while driving the vehicle. There's too much driver-to-driver variance to even begin to accurately estimate "real world" mileage.

The purpose of the EPA mileage figures is to let the car buyer compare the fuel economy of different cars, knowing the numbers are derived from a consistent test run on all cars. If you're looking at a 30 MPG vehicle and a 33 MPG vehicle, you probably won't get exactly 30 and 33 MPG when you drive them. But it's a pretty good bet that when you drive the second vehicle, you'll get 10% higher MPG than when you drive the first vehicle.

Yep... in theory. However, when a car I got in 2005, rated at 22 MPG Highway consistently got 23-24 MPG with my driving, and a car I got in 2011, after the newer, "stricter and more realistic" standards were in place was rated at 33 MPG highway and I consistently get 29-31 MPG, it would seem to me that the EPA sticker is about as useless as paying extra for "undercoat sealing" at the dealer. My reasonable conclusion, was that I'd be easily getting above the highway driving MPG on my new 2012 model, since similar driving in a different vehicle netted me above highway MPG consistently.

Either way, I'm glad to see that an auto manufacturer has been taken to task for their unreasonable claims. Hopefully other auto manufacturers will see this as a call to reel in their overly generous claims.

It might be to compare, but if you can't get the same numbers in reasonable driving conditions (ie mostly highway driving with a light foot), then what's the point in making the numbers? Every car that I have owned since I was 16, I have been able to achieve the EPA numbers if I drive it with a light foot. Even my most recent 2008 VW R32 gets the EPA estimated numbers if I'm not stomping on the gas (which is quite difficult not to....). If you can't reach that EPA estimated number, then there's either something wrong with the car, or the number is wrong. And it wouldn't surprise me if the numbers have been inflated by more than a few manufacturers out there. It's just Hyundai and Kia got caught.

Agreed. The EPA test methods are periodically tweaked to generate results that closer match real world driving conditions. It's the CAFE numbers, which consumers never normally see, that are using an unchanged 30+ year old methodology that gives numbers ~30% higher than the EPA tests. Since the purpose of that test is only to compare relative year/year gains against regulatory targets it needs to be kept constant even though it was almost immediately proven to be unrealistic.